Live Another Day takes place four years after season 8. James Heller, now President, is negotiating a treaty in London, where a hacker collective preaching free information has enlisted the help of Chloe O'Brian. Jack Bauer, who has been tracking the activities of Chloe's group while living in exile, resurfaces when he hears of an imminent attempt on Heller's life.
While anti-drone protesters gather outside the American embassy where James Heller is staying, officers at a CIA outpost in London find and apprehend Jack Bauer. Due to her husband's conviction, Kate Morgan is being forced to hand in her badge. However, she gets herself reinstated when she realizes that Jack is infiltrating the CIA to gain access to Chloe O'Brian. Kate is too late to intervene and Jack breaks Chloe out of interrogation with the help of his friend Belcheck.
Still distrustful of Chloe, Jack follows her to Open Cell, an organization that specializes in leaking government documents. He explains that he is on the trail of Derrick Yates, a former Open Cell member who has become involved in an assassination attempt on James Heller. The attempt is revealed to involve drones when he programs an unmanned aerial vehicle to fire on British and American troops. The pilot, Chris Tanner, is falsely arrested on murder charges.
Jack and Chloe learn that Yates' device has been taken by Margot Al-Harazi, a known terrorist trying to avenge the death of her husband. When their attempt to capture her daughter Simone fails, Jack breaks into the American embassy to analyze Tanner's flight key and prove that the threat is imminent. Jack locks himself in a room with three hostages and tries to upload the data to Open Cell's leader, Adrian Cross.
Marines break in before the upload finishes but Kate Morgan is able to place him in CIA custody instead. In the President's quarters, Chief of Staff Mark Boudreau expresses concerns that Bauer is a terrorist and drafts an agreement for extraditing him to Russia. Suspecting that dementia has clouded Heller's judgement, he forges the President's signature and vows to protect his wife Audrey from any further pain related to Bauer. Jack is ultimately proven right when Margot Al-Harazi broadcasts a video calling for Heller to turn himself in or face attacks on London from six U.S. drones.